EP1222065B1 - Extrusion system comprising a screw changing device - Google Patents

Abstract

The invention relates to an extrusion system comprising at least one screw-type extruder (1) whose at least one screw (4) is drive-connected via a coupling to a gearing (2) that is driven by a motor (3), whereby the coupling can be coupled and decoupled with regard to the screw (4). To this end, a gearing carriage is provided which is configured such that the gearing (2) is mounted on said gearing carriage and such that a small piece can be retracted in order to decouple the coupling in a direction of the longitudinal axis of the screw (4). The gearing carriage can move in pivotal manner or in a manner that is transversal to the longitudinal axis of the screw (4). The gearing (2) can be displaced with the coupling far enough away from the screw (4) so that the screw (4) can then be completely removed from the extruder in a direction that is opposite the feed direction of the screw (4). In addition, a screw changing device (9) is provided through which the existing screw (4) of extruder (1) can be received and can be replaced by another screw (7) located inside said screw changing device (9).

Description

The invention relates to an extrusion system with at least one screw extruder, whose at least one worm has a drive connection with a clutch is a gear driven by a motor, the clutch with respect the screw can be connected and disconnected.

Extrusion systems are used in particular in plastics technology for the production of Plastic products and also for the processing of plastics, i.e. for the production of intermediate products composed of different substances. Extrusion lines for the latter purpose are also called Compounding systems designate and often have extruders with two or more intermeshing snails. In such compounding plants for example additives such as dyes or fiber materials in the plastic raw material mixed in and distributed as evenly as possible in this. Because of the variety of especially thermoplastics and the variety of additives used in their combination have different material properties optimal production snails used in their geometric design optimally to the respective material properties of the material to be processed Material are adjusted. There are also snails that are used for processing a relative wide range of materials are comparatively well suited on average. That means however, that such a snail or such a pair of snails at Processing of the individual materials regularly more or less far from actual operating optimum must work away. This can be done with a corresponding reduction in product quality and / or brings a decrease in production output. Especially in large plants with high throughput rates, special screws are therefore often used for the processing of the respective material is optimally suitable, i.e. with the highest Deliver very good quality production performance.

When processing plastic batches of different materials in smaller ones Quantities mean the use of special screws for the respective material a disproportionately high operating effort because the screws have to be changed So far, it has regularly been relatively expensive, particularly in the form of downtimes the production facility requires. It is therefore common in many companies to use smaller ones To process batches of different substances on special machines, which in are generally less efficient than the large systems for the Main product quantities. Such special machines do not only require one corresponding space requirements, but are often characterized by a relative low degree of utilization. Ultimately, this means that processing is smaller Batches compared to the main production quantities of the standard products is relatively expensive.

DE 3516311 C2 describes a device with a multiplicity of on one Carousel arranged molding stations and one to these molding stations in time Dockable injection unit known with the shoe soles made of polyurethane Shoe uppers are injected. The material components for the liquid polyurethane are in one with a short, fast rotating (15000 to 18000 rpm) and mixing head of the injection unit provided on one side of the mixing screw mixed. The mixing screw bearing can be replaced together with the mixing screw Drive by means of a hydraulic cylinder system, primarily for docking the The mixing head performs the necessary sliding movement on the forming stations, be retracted so that the mixing screw completely out of the mixing head is pulled out before it is uncoupled from the drive and by a hydraulically movable screw changing device for another is exchanged. With longer snails, this solution would be an extremely long one Require installation space. In contrast to injection units, extrusion systems are the The aforementioned type of docking movements are not common, rather it remains so called downstream equipment in its spatial arrangement for Screw extruder unchanged during production.

Furthermore, a screw injection molding machine is known from DE 3643884 A1 the entire injection unit on a spar frame by means of an injection cylinder the injection molding machine can be approached to the injection mold. To change the The screw of the injection unit can drive the entire screw from that Spray cylinder can be retracted a little bit on the spar frame until the worm is uncoupled from the drive. To get the snail out of the To be able to remove the screw cylinder of the injection unit Screw cylinder pivoted about a vertical axis of rotation, so that the screw can be pulled out diagonally past the drive. For the Swiveling the screw cylinder is with a special side attached pivot bearing connected.

The object of the present invention is to provide an extrusion system Generic type to the extent that the effort for Conversion of the extrusion system from processing one material to another other material with different properties is significantly reduced. So it should while maintaining high product quality and high productivity quick material change may be possible.

This task is solved for a generic extrusion plant by the Characteristic features of claim 1. Advantageous further developments of Invention are specified in the dependent subclaims.

The basic idea of the solution according to the invention is a conventional one To provide extrusion system with a device that is particularly fast and easy change of the screw or screws of the extruder. (In the The following is usually only discussed by a snail for simplicity, although the invention of course includes extrusion lines which one or contain several extruders connected in parallel or in series and which in turn include one, two or more snails can be fitted.) The invention provides that the screw is not at the extruder head out of the extruder is pulled out, but that this happens at the other end of the extruder, where the gear unit for driving the worm is attached. This has the great advantage that the subsequent units connected to the extruder head (so-called downstream equipment) when changing the screw must be dismantled. The invention provides that the transmission with its Coupling for coupling and uncoupling the worm on a gear carriage is arranged with which the gear with the clutch from the worm so far is movable away that the screw then completely against its conveying direction the extruder can be pulled out. There is also a screw changing device provided through which the existing screw of the extruder can be taken up and by another screw in the screw changing device is replaceable.

The term geared wagon should not be understood in the narrow sense here that such a gearbox is actually provided with wheels for movement have to be. It could easily be a sledge, for example act that slides on runners in appropriate guides. Preferably, the Gear trolleys, however, are provided with rollers or wheels for movement.

In principle, the geared carriage could also be designed as a swivel unit, so that the transmission with the clutch after loosening the fasteners (e.g. screws) with which the gear unit is firmly connected to the extruder, For example, is pivoted away to the side, so that the clutch at the same time The snail is decoupled and the rear space for pulling the snail against their direction of funding is cleared. Although swiveling to the side is preferred the pivoting movement could in principle also go up or down respectively.

Preferably, the gear carriage is designed such that the gear on the gear carriage is retractable in the direction of the longitudinal axis of the screw in this way to decouple the coupling from the worm. The Geared carriage itself is expediently movable transversely to the longitudinal axis of the worm. The gear unit can be used to decouple the clutch For example, be equipped with a small sled whose runners are parallel to Direction of conveyance of the screw. The two movements to decouple the Coupling and for moving away the gearbox with the flange-mounted on it In principle, the drive motor could also be made possible by the fact that the Gearbox e.g. is provided with steerable wheels.

The screw changing device for mechanized exchange of the screw can as a stationary or movable screw magazine with one Manipulation device for pulling out and inserting a screw be trained. In the simplest case, the screw magazine is with a rotatable one Double arm formed, the one arm for receiving the to be replaced Snail is determined and the other arm carries the new snail. The snail magazine is preferably in the form of a revolver or pater noster magazine designed and therefore suitable for holding a variety of exchange screws. This is a high degree of flexibility with regard to the processing of a corresponding Numerous different materials.

The manipulation device for pulling out or pushing in a screw is preferably a linearly movable slide with a gripping device for Coupling to the respective snail.

Basically, it is possible to track the movements of the gearbox and the To effect manipulation device by an operator. In this case relieves the inventive design of the extrusion system Operator at least from payloads during the dismantling of the old and assembly of the new screw. You can also make the required movements the snails run in guided tracks, so that the time required for one Screw change is significantly reduced.

Even more time is saved if the gearbox and if necessary, the screw changing device each with a motor Drive are provided. This drive is conveniently by an electronic Control operated, the program memory preferably on one fully automatic screw change is set up.

A particularly clear saving effect can be achieved by using one Twin-screw extrusion system equipped according to the invention designed, the screw changing device on the pair Screw change is set up. Such extrusion systems are particularly as Compounding plants for the preparation of thermoplastic plastics advantageous.

Using that shown in the single figure in a highly schematic form The embodiment is described in more detail below.

An extruder 1 designed as a single-screw extruder, its downstream equipment not shown, points to the extruder head opposite end of a gear 2 to which to drive the Extruder screw a motor 3 is flanged. The gear 2, which in the figure in his working position is shown in dashed lines, is not closer to one Coupling shown for coupling the upstream end of the Extruder screw equipped. The gear 2 with the motor 3 flanged to it is mounted on a gear carriage, of which no further details are shown are. For decoupling the coupling of the gear 2 from one still in the extruder 1 the extruder screw can be located in the gear unit, for example after loosening a quick release device with which the transmission 2 during normal Plant operation is firmly connected to the extruder 1, a small piece withdrawn in the direction opposite to the direction of conveyance of the extruder screw. This decoupling path is designated by reference number 11 in the figure Service. After the extruder screw and the coupling are separated have been, the gear carriage in the example shown is transverse to the conveying direction of the extruder 1 shifted to the right by a piece, so that the rear space on the extruder 1 is free for the screw change. The route to Screw change has been designated with the reference number 10. The transmission 2 and the flanged motor 3 are to distinguish it from the dashed Working position in the screw change position with solid lines been shown. The gearbox is in the worm changing position Reference number 5 and the motor with reference number 6. after the If the screw change position has been reached, the screw 4 of the extruder 1 are pulled out of the extruder 1 by means of a manipulation device 8. It is held by a holder of a screw changing device 9. This holder is designed, for example, as a double-arm swivel arm. On the another arm, this double-arm swivel arm is another worm 7 stored, which is to be replaced with the previously used screw 4. For this the manipulation device 8 is released from the screw 4 and a little further scaled back. Then the double-arm swivel arm in the way rotated that the screw 7 comes into the position of the screw 4. By renewed After actuation of the manipulation device 8, the new screw 7 is then gripped and inserted into the extruder 1. The gearbox with the gearbox and the Motor is then released from the worm 7 after retraction Manipulation device 8 from the change position shown with 5 and 6 again brought into the dashed position 2, 3, i.e. initially by the displacement path 10 pushed back to the left and then around the decoupling path 11 back to the im Extruder 1 located screw 7 pushed so that the clutch the transmission 2 is coupled to the new worm 7. In a preferred embodiment of the Invention will be the movements of the gearbox and the Screw changing device 9 or the manipulation device 8 of Motor drives executed by a programmable, not shown electronic control. Because a screw change this way carried out practically without significant personnel expenditure and in an extremely short time can result in very short downtimes for the entire system and as a result, significantly lower downtime costs than was previously the case. This makes it economically justifiable even for small batches of plastics a high-performance large-scale system. This enables production high-quality products at low cost, even with smaller quantities.

Reference symbol list :

1

extruder

2

Gearbox in working position

3

Engine in working position

4

slug

5

Gear in change position

6

Motor in change position

7

AC-worm

8th

manipulation device

9

Screw changing device

10

Sliding path for changing the screw

11

Entkupplungsweg

Claims (11)

1. Extrusion system having at least one screw-type extruder (1), whose screw (4) of which there is at least one is drivingly connected via a clutch to a transmission (2) driven by a motor (3), the clutch being capable of being coupled to and uncoupled from the screw (4), characterised in that a transmission carriage is provided which is so formed that the transmission (2) is capable of being withdrawn a short distance on the transmission carriage in the direction of the longitudinal axis of the screw (4) for disengagement of the clutch, and which is movable pivotably or transversely to the longitudinal axis of the screw (4), so that the transmission (2) can be moved away with the clutch from the screw (4) sufficiently far that the screw (4) can thereafter be completely removed from the extruder opposite to the conveying direction of the screw (4), and in that a screw changing device (9) is provided, whereby the current screw (4) of the extruder (1) can be taken out and replaced by another screw (7) located in the screw changing device (9).
2. Extrusion system according to claim 1, characterised in that the screw changing device (9) is formed as a movable screw magazine with a handling device (8) for removing and inserting a screw (4, 7).
3. Extrusion system according to claim 2, characterised in that the screw magazine is formed as a revolving or paternoster magazine.
4. Extrusion system according to either of claims 2 or 3, characterised in that the handling device (8) is formed as a linearly movable slide with a handle for coupling on the screw.
5. Extrusion system according to one of claims 1 to 4, characterised in that the clutch of the screw (4) can be disengaged from the motor.
6. Extrusion system according to one of claims 1 to 5, characterised in that the transmission carriage is provided with a motor drive.
7. Extrusion system according to one of claims 1 to 6, characterised in that the screw changing device (9) is provided with a motor drive.
8. Extrusion system according to one of claims 5 to 7, characterised in that the drives are actuatable by an electronic control.
9. Extrusion system according to claim 8, characterised in that the electronic control has a programme store, which is set up for fully automatic changing of the screw.
10. Extrusion system according to one of claims 1 to 10, characterised in that the extrusion system is a double-screw extruder and in that the screw changing device (9) is set up for changing the screws in pairs.
11. Extrusion system according to one of claims 1 to 10, characterised in that the extrusion system is a compounding system for preparing thermoplastic materials.

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